Contactor



Jan. `29, 1963 G, R, TQwNsEND 3,076,073

CONTACTOR Filed oct. s, 1960 INVENTOR. GEORGE R. TOWNSEND 3,076,073CNTACTR George R. Townsend, Roanoke, Va., assigner to General ElectricCompany, a corporation ci New York Filed st. 3, 196e, der. No. 6th-343 6Claims. (Ci. Zitti- 87) This invention relates to circuit breakers of aclass which are more frequently referred to as contactors. Moreparticularly the invention relates to an improved construction in acontactor having a normally closed contact and a normally open contact.The new construction specifically relates to improvements in preventingthe bouncing of contacts in such devices.

ln electrical control circuits devices frequently are used having amovable armature associated with an electrornagnet whereuponenergization of the latter brings about movement ot the former tooperate electrical contacts associated with the armature. Normally whenthe device is energized the armature moves in one direction and when thedevice is no longer energized the armature is returned to its initialposition by a spring or other resilient means. Normally the movement ofthe armature is mechanically restricted so that upon returning to theinitial position the energy or inertia of the armature is absorbed byone of the mechanical limiting elements. Where the speed of operation ofthe armature is relatively high and where the magnitude of the movementof the armature is relatively large, frequently the inertia of thearmature produces erratic operation as a result of encountering thelimiting element. Consequently in a device of this nature where thearmature carries contacts which normally become closed when the deviceis deenergzed, the electrical circuit or circuits formed by thesenormally closed contacts sometimes become interrupted resulting inelectrical failures. various means have been used for correcting thiscondition, and in the present in- Vention a novel concept is employedthat results in simple and eicient operation with relatively low cost ofmanufacture.

it is an object of this invention, therefore, to provide an improvedarmature construction in a contacter that is operatedelectromavnetically and which is returned to its initial condition byresilient means.

ln electromagnetic devices having moving armatures which carryelectrical contacts, obiectionable contact bounce may be corrected byreducing the inertia of the armature, or by damping its motion.Correction may be obtained by reducing the inertia of the armatureeither by actual reduction of its mass or by artificially eiiecting areduction of the mass oran increase in damping in connection with thearmatures operation. The present i11- vention is directed to animprovement of this type.

It is therefore another object of the invention to provide an improvedarmature structure in a contactor for stabilizing its motion inconjunction with electrical contacts carried by the armature andcoacting `with stationary contacts.

The novel features of the invention are set forth with particularity inthe appended claims. The invention itself, however, both as to itsorganization and method of operation, together Iwith further objects andadvantages thereof, may best be understood by referring to the followingdescription and the accompanying drawing.

in the drawing FGURE l illustrates an elevation View of a contacterprovided with an improved armature construction. FIGURES 2, 3 and 4 ofthe drawing illustrate the functional operation of the improvedstructure during its operational phases in overcoming inertia of thearmature while at the same time maintaining electrical contact so that acontrolled circuit is uninterrupted.

ditiifi Referring now to FIGURE l a frame l1 is provided with a mountingbracket l5 and a winding 12, an armature 16 being hinged against thebracket l5 to move toward the winding l2 when the latter is energized.The armature lo is substantially a rectangular strip; however, theparticular shape of this strip is immaterial for the purposes of thepresent invention and could take many other forms. Attached to thearmature le is an inverted, U-shaped bracket 17. A contact arm i9 isprovided with contacts Ztl and 22 at each end respectively and with apin or shaft lit which coacts with and is fitted into the bracket i7.The arrangement of the bracket 17 and the shaft 1S may take severalforms also; id est, there may be two brackets 17, one on either edge ofthe armature l@ with the arm i9 supported by the shaft i8 in the bracketi7 lying between the brackets, or there may be a single bracket i7having a cutaway portion in the center thereof for permitting the arm i9to move therein supported by the shaft ld. Contact Z2 has a projectingportion 22a which normally extends partially through the armature lo asindicated in FGURE l. A spring 14 recessed in a well i3 of the windingl2 normally pushes against the projection 22a of the contact 22 therebyurging the armature lr6 avay from the winding l2 through the interactionof the shaft 18, the bracket 17 and the arm l@ and also causes Contact22 to be positioned against a contact 23, the latter being supported byan arm 23a fixed to an insulating block 24 which is fixed to the bracketl5. The contact 2d is arranged to coact to make electrical connectionwith a contact 2l carried by a mounting 21a which in turn is iixed to aninsulating block Z5. Normally, therefore, contacts Z2 and 23 are closedto permit an electrical circuit to be made While contacts 2d and 2l areopen. When the winding l2 is energized the armature lr6 is drawn down,moving with the bracket i7 which bearing upon the shaft 18 carries thearm i9 and its contacts 22. and 2li downward also. Consequently contacts7.2 and 23 are opened and contacts Ztl and 2l are closed.

When the winding l2 is deenergized the armature 16 is released, andunder the urging of the spring 14 the armature Tio and the arm 19,together with its contacts 20 and 22 are forced upwards until contacts22 and 23 impinge. Referring now to FIGURE 2 it will be noted that whencontact 22, urged upwards by the spring ld, iirst encounters contact 23the shaft i3 will be at its upper extremity within the bracket i7 andthe arm i9 will be carried in such a manner that the bent portionholding the contact Ztl impinges against the end of armature 16. Sincethe armature and its associated assembly have movement upwards as aresult of the force of spring ld, the resulting inertia has to beovercome by the force of reaction of contact Z2 against contact 23.Normally there would be a tendency for the contacts Z2 and 23 to reboundas a result of this reactive force; however, any such tendency in thestructure shown in the present invention is counteracted as explainedhereinafter.

Referring now to FiGURE 3 it will be noted that momentarily the arm i9has turned counter-clockwise on its shaft i8 which still remains at theupper extremity of the Usl1aped bracket i7' and the projection 22a ofcontact 2?. now becomes positioned through the hole in the armature i6.As further resistance is encountered between the Contact Z2 and theContact 23 the arm i9 continues to turn counter-clockwise on shaft i8until the end or" the arm if) carrying contact 22 encounters the uppersurface of armature i6 whereupon the continued pressure between thecontacts 22 and 2.3 reverses the direction of rotation of the arm i9until it rests completely against the upper surface of armature ld, theshaft l moving downward in its relationship with bracket i7.

' the art.

As a consequence of the motions of the armature 16 and its assemblycomprising the arm 19, the shaft i3 and the contacts 22 and 2&3,deceleration ot the armature lo is greatly assisted. More important,however, the physical Contact between contacts 22 and 23 remainsuninterrupted since any tendency for these contacts to separate isovercome by the flexibility of the armature assembly and brings about arolling of contact 22 upon Contact 23 as indicated in FIGURES 2, 3, and4 rather than a bouncing action which is obtained normally in contactorsnot provided with the structure oi the present invention.

Contactors having normally closed contacts are used frequently on motorcontrol devices and circuits where separate lields are required forstarting and where electrodynarnic braking circuits are established whenthe energizing power for driving is removed. Consequently, the improvedstructure described above finds widespread use in motor controlapparatus, and provides reliable op` erating characteristics incontacter requirements.

While this invention has been explained and described with the aid of aparticular embodiment thereof, it will be understood that the inventionis not limited thereby and that many modifications will occur to thoseskilled in it is therefore contemplated by the appended claims to coverall such modiiications as fall within the scope and spirit of theinvention.

What is claimed is:

1. In an electromagnetically operated device, a movable armature, aWinding for generating liux to operate said armature, a bearing memberon said armature, a shaft coasting with said bearing, an arm ixed tosaid shaft, a contact at an extremity of said arm, a fixed contact, anda spring seated in a Well in said Winding and passing through an openingin said armature normally urging first said contact against said ixedContact and biasing the operation of said armature.

2. In an electromagnetically operated device, a movable armature, aWinding for generating iiux to operate said armature, a loose-ttingbearing member on said armature, a shaft coacting with said bearing tohave play in a plane perpendicular to the plane of said armature, an armiiXed to said shaft, a Contact at an extremity of said arm, a iixedcontact, and a spring normally urging first said contact against saidfixed contact and biasing the operation of said armature.

3. In an electromagnetically operated device, a movable armature, awinding for generating iiux to operate said armature, an invertedyU-shaped bearing member on said armature, a shaft loosely tted intosaid bearing, an arm carried by said shaft, a Contact at an extremity ofsaid arm, a Xed Contact, and a spring seated in a Well in said windingand passing through an opening in said armature normally forcing saidcontacts together and thereby biasing said armature against operation bysaid linx.

4. In an electroniagnetically operated device, a mov-` able armature, awinding for generating linx to operate said armature, an elongatedbearing member on said armature, a shaft loosely iitted into saidbearing, an arm carried by said shaft, a Contact at an extremity of saidarm, a fixed Contact, and a spring seated in a well in said winding andpassing through an opening in said armature normally forcing saidcontacts together and thereby biasing said armature against Operation bysaid iiux.

5., in an electro-magnetically operated device, a movable armature, awinding' for generating linx to operate said'armature, a verticallyelongated bearing member on said armature, a statt loosely fitted intosaid bearing, an arm carried by said shaft, a contact at an extremity ofsaid arm, a fixed contact, and a spring seated in a well in said windingand passing through an opening in said armature normally forcing saidcontacts together and thereby biasing said armature against operation bysaid flux.

6. In a contact making and breaking structure comprising a iixed contactand a movable contact normally urged into mutual contact by resilientmeans, an arm for carrying at its one extremity the said movablecontact, a shaft supporting said arm, a sloppy bearing into which saidshaft is fitted for pivoting said arm, and a hinged support.

for said bearing whereby after movement of said support opposing saidresilient means to break said mutual contact the said contacts arerestored by said resilient means Without further interruption by theinteraction of said shaft and said bearing and the rotation of said arm.

References Cited in the le of this patent UNETED STATES PATENTS1,176,569 Kjolseth Mar. 2l, 1916 1,231,412 Murphy lune 26, 19172,092,478 Sommermeyer Sept. 7, 1937 2,397,113 Vlglehart Mar. 26, 19462,397,228 Young et al. May 26, 1946 2,441,137 De Anthony May l1, 19482,943,170 Vradenburgh June 28, 196i)

1. IN AN ELECTROMAGNETICALLY OPERATED DEVICE, A MOVABLE ARMATURE, AWINDING FOR GENERATING FLUX TO OPERATE SAID ARMATURE, A BEARING MEMBERON SAID ARMATURE, A SHAFT COACTING WITH SAID BEARING, AN ARM FIXED TOSAID SHAFT, A CONTACT AT AN EXTREMITY OF SAID ARM, A FIXED CON-